1992 F150 with the 5.0 new autolite platinum plugs and oem wires. Rides smooth at higher Roma and shakes at stoplight etc.. almost feels like a misweighted flywheel or something with the vents I've heard but dint know much about. Any help is great thanks.

 

The platinum plugs aren't helping any.

Have you checked for codes?
Checked fuel psi?

Regular Motorcraft or Autolite Copper core plugs is all that is needed for this vintage truck and using anything other can give you problems.

 

OEM wires as in original to the truck?

Verify the firing order....

 

Oem wires that the owner before me had bought at oreilys. The platinum plugs were recommended ny my brother who is a certified Ford mechanic through NASCAR technical institute. I will check the firing order tonight when I get home because I'm at work right now

 

So how many miles or years on them?

Most of the folks teaching those classes were probably not born when these trucks were manufactured. Many on this forum have had the best experience with plain ol' copper plugs.

Great idea. There should be a sticker under the hood with the correct firing order.

 

The wires I've had in the extended can for awhile. Brand new. I just put them in less than 1k miles ago along with the plugs.

 

Run the truck at night, then open the hood where it's dark. Look for signs of arcing. Just because they are newer does not make them good.

 

Alright. I'll do that when I check the firing order tonight. But wouldn't all this make the motor shake more than the transmission? It's right below the hump and my 4wd shifter shakes like crazy so I know out has to be transmission related to some degree.

 

Start with the easy stuff first.

More than once someone on this forum has replaced a transmission or torque converter then found out the problem persists and it was ignition related.

 

Haha I bet that sucked. So yeah that that makes sense. I figured it was along those lines just wanted to be sure.

 

Could this be a motor mount? I have the same issue on a 5.8. Verified no missfires.

 

I'm not sure. I sprayed some throttle body cleaner around the inside of my tb and it seemed to lessen a little bit but not by much

 

+1 on this all I run on mine is regular motorcrafts. I had a issue with e3 diamond fire plugs on a Mitsubishi replacing stock ngk platinums. missed so bad and shaked that it stalled more than once. E3s came out saturated with fuel. Put new ngk plugs in and ran great. Learned my lesson. Unless it's TRULY a built motor( in general) than stock oe replacements are fine.

Edit: that car was doing the same thing you described with the shake at idle. Pull a plug to see if its wet. Could be a incorrect gap or heat range

 

Just thought of this, if the shake isnt too bad it could be the air idle control valve. Might try cleaning with some electronic cleaner.